Valves And Valve Springs; Removing The Valves; Checking The Valves And Valve Guides - Yamaha MT-03 Service Manual

EAS00237

REMOVING THE VALVES

The following procedure applies to all of the
valves and related components.
NOTE:
Before removing the internal parts of the cylin-
der head (e.g., valves, valve springs, valve
seats), make sure the valves properly seal.
1. Check:
• Valve sealing
Leakage at the valve seat
valve face, valve seat, and valve seat width.
Refer to "CHECKING THE VALVE SEATS".
a. Pour a clean solvent "a" into the intake and
exhaust ports.
b. Check that the valves properly seal.
NOTE:
There should be no leakage at the valve seat "1".
2. Remove:
• Valve cotters
NOTE:
Remove the valve cotters by compressing the
valve spring with the valve spring compressor
"1" and the valve spring compressor attach-
ment "2".
Valve spring compressor
90890-04019
Valve spring compressor
attachment
90890-01243

VALVES AND VALVE SPRINGS

3. Remove:
Check the • Valve spring retainer "1"
• Valve spring "2"
• Valve stem seal "3"
• Valve spring seat "4"
• Valve "5"
NOTE:
Identify the position of each part very carefully
so that it can be reinstalled in its original place.
EAS00239
CHECKING THE VALVES AND VALVE
GUIDES
The following procedure applies to all of the
valves and valve guides.
1. Measure:
• Valve-stem-to-valve-guide clearance
Valve-stem-to-valve-guide clearance =
Valve guide inside diameter "a" –
Valve stem diameter "b"
Out of specification
guide.
5-21
Replace the valve